Which figure should replace the question mark (?) if the following series were to be continued?

Correct — D. Four panels are drawn, each holding the same six marks — an up-arrow, N, a triangle, S, 7 and C.
Each panel has a small box in its top-right corner, so there are six fixed places: top-left, the box's top-right, the box's lower-left, centre-left, bottom-left and bottom-right.

Rule: every mark advances one step round the loop arrow → N → triangle → S → 7 → C → arrow.

Top-left reads arrow, N, triangle, S, so it must become 7.
The box's lower-left reads 7, C, arrow, N, so it becomes the triangle.
Bottom-left reads N, triangle, S, 7, so it becomes C.
Bottom-right reads triangle, S, 7, C, so it becomes the arrow.

The last two marks advance and trade places: what sits in the box's top-right moves to centre-left, and what sits at centre-left moves into the box. From panel 4 that sends the arrow on to N at centre-left and the triangle on to S inside the box.

Only option (d) shows 7 at top-left, the triangle in the box, C at bottom-left and the arrow at bottom-right.

Why the others are wrong

• (a)
  Option (a) puts C at top-left. That place runs arrow, N, triangle, S across the four panels, so the next entry is 7 — C is one step further on.
• (b)
  Option (b) also opens with C at top-left, where the loop demands 7. Its bottom-left arrow is wrong too: that place runs N, triangle, S, 7 and needs C.
• (c)
  Option (c) repeats panel 1's top-left arrow, as though the loop had not advanced at all. Four steps on, that place holds 7.

In a symbol-cycle series nothing enters and nothing leaves. The same marks appear in every panel and only their places change, so the work is bookkeeping, not imagination.

Pick one place, write down the four marks that occupy it, and you have a stretch of the loop. Do that for two or three places and the loop closes. You never need to see the whole panel change at once.

Key facts

• All four panels use the same six marks, so none can appear twice or go missing.
• The loop is arrow, N, triangle, S, 7, C and then back to the arrow.
• Top-left alone decides the answer, because only option (d) carries 7 there.
• Four of the six places keep their mark's slot, while the box's top-right and centre-left exchange each step.

Common traps

• Trying to see the panel as one rotating picture when only the marks move.
• Treating the inner box as a separate figure rather than two more places.
• Checking one place, finding a match, and never testing a second one.

No directly related past PYQ was found.